Scorpio 1993 V6 12v efi Lean condition

[davew]

....or perhaps that spare loom is present because they changed it as it is faulty too; Worth swapping over, then run for a while and check for the '41' Code (?)

The problem with these 12v looms is that they touch hot parts of the engine and the insulation flakes off over time. The ECU sends an earth pulse to the injectors to operate them (ie. 'hard 12Volts'supply on the other side) so if that wire 'grounds' it will open the injector and over-fuel....

If you doubt the injectors it may be worth getting/making some 'NOID' lights too...

[Kaptajnen]

If we assume that a periodic ground to one the injectors is the culprit, sending in lots of fuel, would the loss of power when the "thump" appears then be expected?
And if it gets too much fuel, would the ECU retard it so much that it would set a "HO2 no switching for 20 seconds" code?

The NOID sounds like an idea, but as it is periodic i would then rely on being able to "provoke" the shorting, or else it would just show it is working; I will make a thorugh inspection of the injector loom, for starters

I appreaciate the effort!

Thanks.

[davew]

Well if you 'solid earth' the injector ECU feed and thus badly over-fuel it won't ignite, then it might misfire as/if it clears...... (?)

Yes, check the loom for possible roblems first. A noid would simply show a 'solid earth' feed as opposed to switched/pulsed !

[Kaptajnen]

Hi All

I haven't got the time yet to start the physical search for faults, but I did spend some money in the G&S shop getting the engine management fault finder.
Funny enough, code 41 is Rich running, and not Lean!?! according to the book.
This complies pretty well with the low milage and the theory with the open injector; although the spark plugs still would indicate lean running, as far as I know.

[davew]

Yes could be the 'stuck injector issue as discussed'; But are you saying that you now suspect a spark plug is faulty ? (As if flooded again then the mixture won't combust)



https://www.troublecodes.net/ford/eec-iv/

[Kaptajnen]

I don’t suspect A faulty spark plug, these were replaced last year.
But if the code says Rich running, i would suggest the Colour of the spark plug indicating lean running.
In the link you posted code 41 is lean, But in the engine management book i posted A picture from 41 is Rich
Which one is right then?

[davew]

Well spark plugs/HT leads etc can fail at any time of course.

The issue of 'leaness' or 'richness' of mixture can occur to differreing degrees and/or may be intermittent,
in other words it may not show up on your plugs.

The main point is it is generally fuel (eg. injectors) or electrical (eg. HT or other wiring)..
The exception here being suspect Hego wiring, as mentioned before.

Not sure just which Ford manual gave you that 41 Code as 'Rich' but it isn't !

[Kaptajnen]

I bought the appropiate book from the granada scorpio shop
Regardless of this being A lean or Rich running issue, i have somewhat A intermittent mixture problem; if Its A wiring or mechanical error Time Will Tell.
I believe i should get a crack on the fault finding mission and See were it takes me.

I appreciate all the effort!!
Thanks A lot!

[davew]

Ah, that book... invaluable but some of these have the odd 'typo' too !

[Kaptajnen]

Hi All

So; the first attempt on cracking the fault came this far:
We did some preliminary tests, and found the exhaust manifold gasket on left bank to be done, the vacuum exited from here when the other exits was blocked, this shouldn't have any effect on a lean running issue.
The Hego is regulating as i should.

The thing we then found, was - and its about here I'm wetting myself; there were some melted wires at the PCM, which at first sight didn't look like a problem, but further investigation showed it had done a small rip on the blue/white wire to the hego; the thump i had experienced on a couple occasions appears to be A perfect ground to the PCM which would have nuked the PCM resulting in a collapse while running - i cant imagine what kind of signals the PCM would have used with a quite unauthorized ground to the system.

We are quite certain that the thumps, are solved; we need to check the wiring thoroughly and we need to check the source of the melted wires to be sure that it isn't acting up another place in the car.
The green/white wires, that have melted, are assembled in a small plug just about the PCM and have been disconnected, or perhaps never assembled as it still contains grease on the plug; but why have they then melted?
I bought the 92 wiring book from the shop, but it ends on page 31; our search for these wires are on page 33.1.1. does anybody know where i can find this page, or what schematics i can find it in?
So far we tracked it to be perhaps to the door locking system, but why is it going to the PCM? Also, it appears to be used only in cars with an auto box?

The car haven't been started up since it last blew up in my face, and when we checked the spark plugs they were as white as a new one, under our tests, when in ran in the closed loop management, it got at healthier looking brown colour.
after we found and isolated the wiring fault, we took it for a spin, were it drowe nicely and accelerated smooth to about 90mph
We checked the plugs, and they were white again, but no code in KAM; perhaps it runs as it should, or perhaps we need to do some further investigation.
Just a small update
Thanks.

[davew]

Ah... you mean the Hego circuit was faulty as I had suggested/suspected last July ??

Grounding the Hego inputs would not be totally disastrous in fact.... these sensor inputs to the PCM are reasonably protected against such grounding - but generally NOT 12 volts...(eg. the heater supply).. which might fry them...)

Not sure just what you are tracking on your wiring there, explain this further and maybe someone can assist.... (?)

[Kaptajnen]

Hi Dave
Your suggestion appears to have been quite in the right direction
Last year when measured upon the hego, nothing were to suspect; other than the heating element of the hego was dead, also, as of now when measured upon, no signs were given that there were any faults to the hego wiring i.e. it were switching on the multimeter.
But damaged wires were found, and in collaboration with the blue/white wire to the hego; whatever fault this could result in, i have no clue, if you dont suspects the shortening to be a problem?

The wire have been isolated, and took the car for a drive in about an hour, some small trips around town for some errands, and then took it out of town for a 16 mile spin.
It appeared to be driving fine, but again, it has been all the time when the thumps appears out of now where; no code logged in KAM, but the spark plug were very white!

The pins in question is Pin 30, brown/white, which are assembled in a plug with pin 18 black/red, and then splits in 2xbrown/white - these 2 brown/white are the ones that are quite fried; in the engine management books, these wires run to the immobilizer, which are found on page (diagram) 33.1.1, which i dont have; i dont have an immobilizer either.
In the 92 diagram book it just runs to the fuse box; the other day, i traced one of the brown/white wires to the door, so i would suspect the other brown/white wire would run to the other front door, but that's not what the diagram tells me?
So i am confused.. yet again.

Thanks again for the help, it is appreciated.

[davew]

The effect of shorting on the Hego wiring depnds on just what was shorted (and for how long...)

The most standard gauge of wiring is on these cars is usually god for 5-10 amps continuous; What you descrided sounds more like 15-20 amps.

Previously you mentioned sone 'gease' too: Is it possible you are just looking at a wire that was soldered plus some flux residue ? From your original posts it sounds like a previous owner modified something associated with the Hego wiring (and so it is hard to know just what he did - and why !)

On the wiring diagram photo you posted up I can't really discern the designations clearly either.... but if it is somehow associated with door alarm/immobiliser etc wiring then then it is not associated with the Hego of course...

[Kaptajnen]

Hi Dave

Sorry for my late reply; I'm a bit short on time lately
See attached photos; one shows the 2 pin plug from the PCM, and the other the damage on the wires; i assume the plugs had been connected by mistake, otherwise i can't see how the wires could have taken damage.
The blue/white wire from the Hego were in the small "Y" section i have encircled, this made a very small opening to the copper, so it were shortening to the brown/white wire, which i haven't located were runs to yet.

Could you please explain what "gease" is

I will try making a better wiring diagram!

Thanks

[Kaptajnen]

So; the season is well upon us, and the Scorpio were A fond receiver of A day of attention,
New oil and filter, new power steering oil, new discs and pads in the front, and A nip and tuck of the rear brakes.
The radiator has a very small leak, which is being solved with a new one, and one of the exhaust mounts were hanging by A thread!, I have bought new ones from powerflex
When it was on a lift i found the "missing" HEGO; it does have one on each bank, but the left bank side is indeed hard to find when not on A lift!
When the exhaust mounts is exchanged, i will probably exchange the Hego as well, as I have a spare in stock
We didn't find anything in the disc wear warning light problem, as nothing were visible defect, so perhaps a bad ground somewhere?

In regards to driving issues, the infamous thump have not shown its ugly face, i believe i already have been driving more this year than all of 2019; but it did show out of nowhere, i have my fingers crossed!

A very good season to all!

[Kaptajnen]

Hi All
The season is about to start soon and im planning the projects of the year.
I got at new radiator, but the small leak have stopped again, perhaps ill change it anyway; the new powerflex exahaust mount is to be fitted so i don't loose the exaust on the road and i got a new dual tone Cosworth horn as the old were probably gunged up, and didnt work when parked for the winter; it did though have a small whine during the winter start up.

In the bigger projects department, the tappets does make some noise, and my very skilled mechanic would like to check adjustement though they should be hydraulic.
What i can find, the heads needs to be removed to exchange the tappets on the 12v, can anybody confirm this?
If its somewhat straight forward im considering the exchange when we have it parted anyways.

In the upgrading department, i got a set of electric seat consoles, hopefully these will get mounted this spring.

Thanks!

[davew]

Hi Kaptajnen, looks like you are soon going to be busy, as many of us could be soon as Spring arrived so early !?

Yes, your 'lifters'/tappets are hydraulic, so self-adjusting...... It's good to know you have a skilled mechanic but not one who does not actually know if the heads should come off to swap out the lifters !? (Yes !)

[Kaptajnen]

I hopefully will!
I should get some tires for the freshly paintet 16" cossie rims aswell!

Maybe he knows, maybe not, we didn't discuss the details about it, im just doing my own research in these matters.

[davew]

Fair enough Kaptajnen... you don't want to go to the trouble of taking the heads off etc just to find they are non-adjustable hydraulic lifters though ?!
(although some earlier Ford lifters are adjustable).....

Forgot to ask what 'weight' oil you are using, and what your current mileage(kilometreage ?) is... These engines all get a bit 'tappety' (noisy) after ~100K miles of course

Wheel looks good; No 'kerbing' though !

[Kaptajnen]

If heads are removed i suppose the valves should be measured and reseated, and perhaps the head should be resurfaced?
Or do i make to much of it?

It runs 5w30, and is about 247000 km, 150000 miles, so i believe its reasonable if some wear is beginning to show.